QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

south of the Aleutian Islands

Yes. A magnitude 2.9 earthquake was recorded south of the Aleutian Islands at 03:46 UTC on 2023-09-19, 10 km deep.

· 10 km deep · released about 680 lb of TNT

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10 km30 km60 km120 km N
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 2.9 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest mapped fault
Alaska-Aleutian subduction zone, 15 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1077 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 30 km (19 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km in our catalogue was M 5.2 on 2019-08-03 — about 2,800 times the energy of this one.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 52.1686, -165.8539. Map © OpenStreetMap contributors.

Aftershocks so far

58 earthquakes have been recorded within 50 km since this one.

  1. 2.5 224 km SE of Nikolski, Alaska
  2. 3.1 193 km SSE of Unalaska, Alaska
  3. 2.6 189 km SSE of Unalaska, Alaska
  4. 2.8 199 km SSE of Unalaska, Alaska
  5. 2.8 172 km SSE of Unalaska, Alaska
  6. 2.8 189 km SSE of Unalaska, Alaska
  7. 2.9 197 km S of Unalaska, Alaska
  8. 2.6 189 km SSE of Unalaska, Alaska
  9. 2.4 184 km SSE of Unalaska, Alaska
  10. 2.9 190 km S of Unalaska, Alaska
  11. 2.6 209 km S of Unalaska, Alaska
  12. 3.4 195 km S of Unalaska, Alaska
  13. 2.6 203 km ESE of Nikolski, Alaska
  14. 3.2 200 km ESE of Nikolski, Alaska
  15. 4.2 213 km S of Unalaska, Alaska

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.